The present invention relates generally to containers useful for products that may be poured from the container and, more particularly, to improved closures secured to said containers. For example, paperboard cartons are generally well known. A familiar type is the milk carton which has a gabled top. Also, becoming ever more popular are rectangular shaped cartons, some of aseptic quality, for containing beverages, powdered goods, and practically any other pourable substance. To prevent waste and provide for ease of pouring, improved pour-through closure apparatus for securing openings in said containers are needed. Practically any container to be used to hold pourable contents may benefit from the improved closure of the present invention.
Push-tabs have been used in combination with container closure apparatus, which are designed to be depressed into the material of the container or package. The push-tabs serve to open a partially pre-cut area on the surface of the package below the closure. The push-tab separates the material of the package and may serve to hold the material apart to maintain the opening during pouring.
Previous closure push-tabs have been hinged directly to an inner wall that defined a central opening in the closure apparatus. The present invention recognizes a need for improved force distribution through the hinge, when the push-tab is depressed by a user of the container. By improving the push-tab hinge design, stress distribution through the hinge is improved. As a result of the hinge design improvements, the closure apparatus may be manufactured from a broader range of materials, some of which may be less expensive.
The present invention provides a push-tab hinge which distributes stresses more effectively than previous hinge designs. In particular, the present invention provides a landing which extends from the closure opening to a spring face which depends from the push-tab. The junction between the landing and the spring face provides a first flexible joint through which the hinge acts. The junction between the spring face and the push-tab provides a second flexible joint through which the hinge acts. Furthermore, an air vent in the hinge is adapted to facilitate a substantially even flow rate of a product through the closure opening.
The entire apparatus may be made as a one-piece injection molded plastic unit, having movable parts. Reference is made to U.S. Pat. No. 5,101,999, which is hereby incorporated by reference into the present application.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and preferred embodiments.